Cream margarine in a mixing bowl.
Beat in sugar, eggs, 2 T. cocoa,
flour, pecans and vanilla.(first 7 ingredients)
Pour into greased glass dish.
Micro on med. for 7 minutes. Rotating every 2 minutes.
Then micro on high for 3 minutes. Rotating once.
Remove from micro and cover with marshmallows.
Let stand 5 minutes while mixing icing.
Mix powdered sugar and cocoa in 1 quart mixing bowl. Add milk.
Microwave on high 2 minutes. Stir in vanilla. Pour over cake.